旧密码确认

如何解决旧密码确认

我在更改密码时遇到问题。我想通过确认旧密码然后更改密码来简化它。这是我的代码

Private Sub btnCChangePass_Click(sender As Object,e As EventArgs) Handles btnCChangePass.Click


    Dim ConnString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\VB.net\My Projects\InventoryData.accdb"
    Dim sqlString As String = "Update Cridentials SET [Password] = @pass"
    Dim pass As String = "SELECT [Password] from Cridentials"
    Dim conn As New OleDbConnection(ConnString)
    conn.open()

    'this part is my problem
    If (txtCOldPass.Text <> pass) Then
        MsgBox("Wrong Old Password",MsgBoxStyle.Critical,"Password not matched")

    ElseIf txtCOldPass.Text = nothing And txtCNewPass.Text = nothing And txtCConPass.Text = nothing Then
        MsgBox("Please submit the following information","Incomplete")

    ElseIf txtCNewPass.Text <> txtCConPass.Text Then
        MsgBox("New Password and Confirm Password in not matached","Incomplete")

    Else

        Using con As New OleDbConnection(ConnString)

            Using cmd As New OleDbCommand(sqlString,con)

                cmd.CommandType = CommandType.Text

                cmd.Parameters.AddWithValue("@pass",txtCNewPass.Text)


                con.open()

                cmd.ExecuteNonQuery()

                con.Close()

            End Using

        End Using
        MsgBox("Changing password Success!",MsgBoxStyle.information,"Successs!")
        Me.Close()
        Form1.Show()

    End If
    txtCOldPass.Focus()
    txtCOldPass.Clear()
    txtCNewPass.Clear()
    txtCConPass.Clear()

End Sub